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Tytuł:
Recent advances in mode converters for a mode division multiplex transmission system
Autorzy:
Memon, A. K.
Chen, K. X.
Powiązania:
https://bibliotekanauki.pl/articles/1818205.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Stowarzyszenie Elektryków Polskich
Tematy:
integrated optical device
mode converters
mode division multiplex
optical waveguide
Opis:
Adopting mode division multiplex (MDM) technology as the next frontier for optical fiber communication and on-chip optical interconnection systems is becoming very promising because of those remarkable experimental results based on MDM technology to enhance capacity of optical transmission and, hence, making MDM technology an attractive research field. Consequently, in recent years the large number of new optical devices used to control modes, for example, mode converters, mode filters, mode (de)multiplexers, and mode-selective switches, have been developed for MDM applications. This paper presents a review on the recent advances on mode converters, a key component usually used to convert a fundamental mode into a selected high-order mode, and vice versa, at the transmitting and receiving ends in the MDM transmission system. This review focuses on the mode converters based on planar light wave circuit (PLC) technology and various PLC-based mode converters applied to the above two systems and realized with different materials, structures, and technologies. The basic principles and performances of these mode converters are summarized.
Źródło:
Opto-Electronics Review; 2021, 29, 1; 13--32
1230-3402
Pojawia się w:
Opto-Electronics Review
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Helically twisted long-period fiber gratings of YOFC single-mode fiber with optical fiber welding machine
Autorzy:
Bai, Yunfeng
He, Zelong
Bai, Jiyuan
Dang, Suihu
Powiązania:
https://bibliotekanauki.pl/articles/2033950.pdf
Data publikacji:
2021
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
YOFC single-mode fiber
helically twisted long-period fiber grating
fundamental mode
cladding mode
coupled mode theory
Opis:
The single-mode fiber provided by YOFC inc is employed for spiral processing by commercial welding machine. It can clearly see the periods structure under the light, but there is no obvious deformation of the fiber core, cladding and surface morphology under a microscope. There is an obvious resonant peak near 1560 nm, half peak width is about 25 nm, the depth of the resonant peak closed to –26 dB, when the period is about 411 μm. It agrees with theoretical calculation results according to the long-period fiber grating coupled-mode theory. The resonance wavelength is caused by coupling between the fundamental mode and the LP14 mode. The responsivities of the helically twisted long-period fiber gratings (H-LPFG) for the temperature is measured, the resonance wavelength is linear with temperature, the slope is 86 pm/°C. Because it is easy to inscribe by commercial welding machine, and has a strong resonance peak, it has potential applications as the temperature sensor.
Źródło:
Optica Applicata; 2021, 51, 3; 407-413
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Differential and Common Mode Noise Waves and Correlation Matrices
Autorzy:
Dobrowolski, J. A.
Powiązania:
https://bibliotekanauki.pl/articles/226394.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
differential and common mode noise waves
mixed-mode noise wave correlation matrices
generalized multiport mixed-mode noise wave correlation matrice
Opis:
This paper presents an innovative extention of the noise wave definition to mixed mode, differential – and common-mode noise waves which can be used for noise analysis of differential microwave networks. Mixed mode noise waves are used next to define generalized mixed mode noise wave correlation matrices of microwave multiport networks. Presented approach may be used for noise analysis of microwave differential networks with differential ports as well as with conventional single ended ports.
Źródło:
International Journal of Electronics and Telecommunications; 2014, 60, 2; 133-141
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mixed Mode Survey Design: problem efektu techniki
Mixed Mode Survey Design: Mode Effect Problem
Autorzy:
Sztabiński, Franciszek
Żmijewska-Jędrzejczyk, Teresa
Powiązania:
https://bibliotekanauki.pl/articles/412876.pdf
Data publikacji:
2012
Wydawca:
Łódzkie Towarzystwo Naukowe
Tematy:
Total Survey Error
błąd braku odpowiedzi
efekt techniki
Mixed Mode Survey Design
Europejski Sondaż Społeczny
Non-Response Error
Mode Effect
European Social Survey
Opis:
W sytuacji pogarszających się warunków realizacji badań surveyowych poszukuje się sposobów ograniczenia błędu pomiaru (Total Survey Error), związanego z nieuczestniczeniem wylosowanych jednostek w wywiadzie (Non Response Error). Jedno z rozwiązań stanowi procedura Mixed Mode Survey Design, która polega na uzyskiwaniu tych samych informacji od różnych osób, przy wykorzystaniu odmiennych technik badawczych, np. wywiad PAPI (Paper and Pencil Interviewing), CATI (Computer Assisted Telephone Interviewing), CAWI (Computer Assisted Web Interviewing). Jednakże wykorzystanie tej procedury może powodować wystąpienie efektu techniki (tzw. Mode Effects). W artykule analizujemy efekt techniki na płaszczyźnie: (i) sformułowania pytania; (ii) sposobu kontaktowania oraz (iii) sposobu komunikowania się z respondentem, poddając ocenie wskaźnik realizacji (tzw. Response Rate) oraz porównując odpowiedzi respondentów na te same pytania, uzyskane przy zastosowaniu różnych technik. W analizach wykorzystano materiały zebrane w projektach realizowanych techniką PAPI (badanie European Social Survey, round 3) oraz CATI (badanie w ramach metodologicznego grantu ESS Infrastructure: i3.). Wyniki przeprowadzonych analiz potwierdzają istnienie poważnych różnic związanych z efektem techniki (w przypadku wywiadu PAPI i CATI). Stawia to pod znakiem zapytania ideę ich łączenia celem ograniczenia błędu braku odpowiedzi.
The fieldwork conditions for surveys becomes progressively worse so methods are being sought to reduce the total survey error arising from non-response error. One solution is the mixed mode survey design procedure whereby the same information is obtained from different respondents, using different data collecting modes (e.g. PAPI, CATI, Web survey). However, this procedure may produce the so-called mode effect. In this paper, we analyse the mode effect from the following perspectives: (i) wording of questions, (ii) contacting mode, and (iii) mode of communication with the respondent. We assess response rates and compare respondents’ answers to the same questions obtained through different techniques. Our analysis is based on materials collected in research projects employing two modes PAPI (the European Social Survey, Round 3) and CATI (ESS Infrastructure: i3, a study funded under a methodological grant). The findings from our analysis confirm the existence of significant differences related to the mode effect (in the case of PAPI and CAPI). Those findings challenge the idea of combining those modes to reduce non-response error.
Źródło:
Przegląd Socjologiczny; 2012, 61, 1; 31 - 63
0033-2356
Pojawia się w:
Przegląd Socjologiczny
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Adaptive fuzzy-sliding mode controller for trajectory tracking control of quad-rotor
Autorzy:
Simoud, Lahcen
Kadri, Boufeldja
Bousserhane, Ismail Khalil
Powiązania:
https://bibliotekanauki.pl/articles/384825.pdf
Data publikacji:
2020
Wydawca:
Sieć Badawcza Łukasiewicz - Przemysłowy Instytut Automatyki i Pomiarów
Tematy:
quadrotor UAV
sliding mode control
adaptive PD-Slidng mode controller
fuzzy PD-sliding mode
Opis:
This paper deals with the design of an adaptive-fuzzy-PD-Sliding mode controller to achieve stabilization of a quadrotor aircraft in the presence of wind disturbance. Firstly, the dynamic system modeling is carried out using Euler-Lagrange formalism. Then, an adaptive PD-sliding mode control system with an integral-operation switching surface is investigated for quadrotor desired trajectory tracking. Finally, an adaptive fuzzy-PD-sliding mode controller is proposed to achieve control objectives and system stabilization where the fuzzy logic system used to dynamically control parameters settings of the PD-sliding mode equivalent control law. Effectiveness and robustness of the proposed control scheme is verified through simulation results taking into account external disturbances. The simulation results of a quadrotor aircraft control with the proposed controller demonstrate the high performance during flight such as null tracking error and robustness in the presence of external disturbances.
Źródło:
Journal of Automation Mobile Robotics and Intelligent Systems; 2020, 14, 2; 15-24
1897-8649
2080-2145
Pojawia się w:
Journal of Automation Mobile Robotics and Intelligent Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Declarative and Behavioral Data in Predicting Respondents Survey Mode Preference
Autorzy:
Rybak, Adam
Powiązania:
https://bibliotekanauki.pl/articles/1790392.pdf
Data publikacji:
2020-06-24
Wydawca:
Polskie Towarzystwo Socjologiczne
Tematy:
European Social Survey
survey mode preference
mixed-mode survey design
adaptive survey design
Opis:
Using previously established knowledge about survey mode preferences distribution in a population can be one of many ways of improving representativeness and quality of data gathered by survey research. Apart from mode preference existence and stability, the main problem concerns the question: which of the sources of information about mode preference could be treated as trustworthy. Because real observed choices are typically treated as better predictors of future choices than declaration only, this paper tries to answer the question: ‘Are the declarations a good predictor of preference in comparison to real choices?’ For this purpose, it uses combined data from 1) the 2015 Polish mixed-mode ESS experiment and 2) data from ESS8 in Poland. The multinomial logistic regression survey preference model includes socio-demographic variables accompanied by declaration/choice control variable. The results suggest significant differences between choices/declarations. Findings could be used to refine the contact strategies used in surveys.
Źródło:
Polish Sociological Review; 2020, 210, 2; 219-228
1231-1413
2657-4276
Pojawia się w:
Polish Sociological Review
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Sliding Mode Control of Hybrid Renewable Energy System Operating in Grid Connected and Stand-Alone Mode
Autorzy:
Benadli, Ridha
Bjaoui, Marwen
Khiari, Brahim
Sellami, Anis
Powiązania:
https://bibliotekanauki.pl/articles/1955980.pdf
Data publikacji:
2021
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
sliding mode control
grid-connected mode
stand-alone mode
hybrid renewable energy system
wind turbine
photovoltaic
battery energy storage system
maximum power point tracking
Opis:
This paper studies innovative application of sliding mode control (SMC) for a Hybrid Renewable Energy System (HRES) in grid-connected and autonomous modes of operation. The considered HRES includes a photovoltaic (PV), wind turbine (WT) based on a Permanent Magnet Synchronous Generator (PMSG). The PV generator is coupled to the common DC bus via a DC/DC converter. The latter is controlled by an MPPT algorithm based on the Adaptive Perturbation and Observation Algorithm Method (APOAM) to search the optimum working of this source. A SMC is utilized to manage the PV voltage to achieve the Maximum Power Point (MPP) by altering the obligation duty cycle. The battery interfaced by a bidirectional buck-boost DC/DC converter can be charged or discharged depending on the production situation. On the one hand, the wind turbine conversion chain is equipped with a PMSG and a rectifier controlled to regulate the operating point of the wind turbine to its optimum value. During a Stand-Alone Mode (SAM) operation, the Voltage Source Converter (VSC) was used for controlling the output voltage in terms of amplitude and frequency delivered to the AC load. However, in Grid-Connected Mode (GCM) operation, the VSC was adapted to control the electrical parameters of the grid. To better appreciate the advantages of the proposed SMC approach, we have proposed a series of comparative tests with the conventional PI control in the operating modes GC and SA and under different scenarios. The proposed control strategy has undeniable advantages in terms of control performance and very low total harmonic distortion THD value compared with the conventional PI control. Finally, It is concluded that the proposed approach improves the quality and provides a stable operation of the HRES.
Źródło:
Power Electronics and Drives; 2021, 6, 41; 144-166
2451-0262
2543-4292
Pojawia się w:
Power Electronics and Drives
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of High-Performance Near-threshold Dual Mode Logic Design
Autorzy:
Bikki, Pavankumar
Powiązania:
https://bibliotekanauki.pl/articles/226748.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
CMOS logic
dual mode logic
dynamic mode
high performance
minimum energy point
near-threshold
Opis:
A novel dual mode logic (DML) model has a superior energy-performance compare to CMOS logic. The DML model has unique feature that allows switching between both modes of operation as per the real-time system requirements. The DML functions in two dissimilar modes (static and dynamic) of operation with its specific features, to selectively obtain either low-energy or high-performance. The sub-threshold region DML achieves minimum-energy. However, sub-threshold region consequence in performance is enormous. In this paper, the working of DML model in the moderate inversion region has been explored. The near-threshold region holds much of the energy saving of subthreshold designs, along with improved performance. Furthermore, robustness to supply voltage and sensitivity to the process temperature variations are presented. Monte carol analysis shows that the projected near-threshold region has minimum energy along with the moderate performance.
Źródło:
International Journal of Electronics and Telecommunications; 2019, 65, 4; 723-729
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Filtered integral sliding mode control in a two-mass drive system
Autorzy:
Dróżdż, P.
Szabat, K.
Powiązania:
https://bibliotekanauki.pl/articles/1193310.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
filtered integral sliding mode control
integral sliding mode control
two-mass system
chattering alleviation
Opis:
The paper presents issues related to the application of filtered integral sliding mode control to a two-mass drive system. A classical control structure has been presented and its design procedure is shown in detail. The properties of the classical structure, in which the chattering phenomenon seems to be a big drawback, have been summarized. In order to eliminate this phenomenon, an output low-pass filter has been proposed and the performance of this system has been tested. In order to improve its characteristics, an adaptive low-pass filter has been proposed. The bandwidth of the filter was changed on-line by the fuzzy system according to the current state of the plant. During the steady-states, the bandwidth is low to eliminate chattering effect, and during transients higher in order to ensure the fast dynamics of the plant.
Źródło:
Power Electronics and Drives; 2017, 2, 37/1; 121-134
2451-0262
2543-4292
Pojawia się w:
Power Electronics and Drives
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
R-Mode receiver development for medium frequency signals
Autorzy:
Grundhöfer, L.
Gewies, S.
Powiązania:
https://bibliotekanauki.pl/articles/134934.pdf
Data publikacji:
2018
Wydawca:
Akademia Morska w Szczecinie. Wydawnictwo AMSz
Tematy:
Global Navigation Satellite Systems
GNSS
GPS
R-mode technology
R-mode receiver
LORAN-C
maritime radio beacons
Opis:
Signals from Global Navigation Satellite Systems are the primary source for Position, Navigation and Time (PNT) information onboard any vessel today. As these signals are prone to interference, a maritime backup system is needed to provide reliable PNT data, R(anging)-Mode is such a system. It utilizes existing maritime radio beacons or base stations of the Automatic Identification System (AIS) by adding ranging components to the legacy signals. The first modified radio beacons transmit medium frequency (MF) R-Mode signals in northern Germany. This paper has described the current state of the authors’ research and development activities at the receiver level for MF R-Mode signals. The receiver platform has been introduced, which was based on off-theshelf components and the implemented algorithms for distance estimation have been explained. Furthermore, the results of the first ranging measurements have been presented, which have shown the general suitability of the R-Mode technology as a source for maritime positioning and timing data.
Źródło:
Zeszyty Naukowe Akademii Morskiej w Szczecinie; 2018, 56 (128); 57-62
1733-8670
2392-0378
Pojawia się w:
Zeszyty Naukowe Akademii Morskiej w Szczecinie
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A window based method to reduce the end-effect in Empirical Mode Decomposition
Autorzy:
Cotogno, M.
Cocconcelli, M.
Rubini, R.
Powiązania:
https://bibliotekanauki.pl/articles/328237.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Polskie Towarzystwo Diagnostyki Technicznej PAN
Tematy:
empirical mode decomposition
intrinsic mode function
end-effect problem
windowing
Opis:
Empirical Mode Decomposition technique (EMD) is a recent development in non-stationary and non-linear data analysis. It is an algorithm which adaptively decomposes the signal in the sum of Intrinsic Mode Functions (IMFs) from which the instantaneous frequency can be easily computed. EMD has proven its effectiveness but is still affected from various problems. One of these is the “end-effect”, a phenomenon occurring at the start and at the end of the data due to the splines fitting on which the EMD is based. Various techniques have been tried to overcome the end-effect, like different data extension or mirroring procedures at the data boundary. In this paper we made use of the IMFs orthogonality property to apply a symmetrical window to the data before EMD for end-effect reduction. Subsequently the IMFs are post-processed to compensate for data alteration due to windowing. The simulations show that IMFs obtained with this method are of better quality near the data boundaries while remaining almost identical to classical EMD ones.
Źródło:
Diagnostyka; 2013, 14, 1; 3-10
1641-6414
2449-5220
Pojawia się w:
Diagnostyka
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Sliding mode control for longitudinal aircraft dynamics
Autorzy:
Iskrenovic-Momcilovic, O.
Powiązania:
https://bibliotekanauki.pl/articles/385149.pdf
Data publikacji:
2018
Wydawca:
Sieć Badawcza Łukasiewicz - Przemysłowy Instytut Automatyki i Pomiarów
Tematy:
aircraft dynamics
control
elevator
longitudinal
sliding mode
Opis:
The control of the longitudinal aircraft dynamics is challenging because the mathematical model of aircraft is highly nonlinear. This paper considers a sliding mode control design based on linearization of the aircraft, with the pitch angle and elevator deflection as the trim variables. The design further exploits the decomposition of the aircraft dynamics into its short-period and phugoid approximations. The discrete-time variable structure system synthesis is performed on the base of the elevator transfer function short-period approximation. This control system contains a sliding mode controller, an observer, based on nominal aircraft model without finite zero and two additional control channels for the aircraft and for the aircraft model. The realised system is stable and robust for parameter and external disturbances.
Źródło:
Journal of Automation Mobile Robotics and Intelligent Systems; 2018, 12, 3; 55-60
1897-8649
2080-2145
Pojawia się w:
Journal of Automation Mobile Robotics and Intelligent Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dylematy związane z estymacją dominanty wynagrodzeń
Dilemmas relating to mode estimation of wages and salaries
Autorzy:
Błażej, Mirosław
Gosińska, Emilia
Powiązania:
https://bibliotekanauki.pl/articles/2156752.pdf
Data publikacji:
2022-12-30
Wydawca:
Główny Urząd Statystyczny
Tematy:
dominanta
estymator jądrowy
estymacja dominanty
histogram
mode
kernel estimator
mode estimation
Opis:
Dominanta wynagrodzeń to ważny wskaźnik opisujący rozkład wynagrodzeń, ale ze względu na silną asymetrię rozkładu tej cechy w Polsce jej wyznaczenie nie należy do standardowych działań w analizie struktury wynagrodzeń. Celem artykułu jest omówienie wybranych metod szacowania dominanty oraz porównanie wyników jej estymacji otrzymanych za pomocą różnych metod. Wykorzystano dane o wynagrodzeniach indywidualnych brutto w październiku 2018 r. pochodzące z badania struktury wynagrodzeń przeprowadzonego przez Główny Urząd Statystyczny. W przypadku metody standardowej, wykorzystującej wzór interpolacyjny i histogram, wartość oszacowanej dominanty jest wrażliwa na założoną rozpiętość przedziałów w szeregu rozdzielczym i początek pierwszego przedziału. Zmniejszanie rozpiętości przedziałów powoduje dążenie dominanty do wartości równej płacy minimalnej. Zastosowanie zaawansowanych metod statystycznych, m.in. wykorzystujących estymator jądrowy, prowadzi do otrzymania znacząco różnych oszacowań dominanty w zależności od metody (rozrzut wyników wynosi ok. 800 zł). Analiza otrzymanych wyników daje ponadto podstawy do rozważenia tezy, że rozkład wynagrodzeń jest mieszany: ma cechy rozkładu dyskretnego dla wynagrodzeń w wysokości płacy minimalnej i ciągłego – dla wynagrodzeń powyżej płacy minimalnej oraz odznacza się cyklicznością (w Polsce zawiera się więcej umów, w których kwota wynagrodzenia jest wielokrotnością 50 zł lub 100 zł, niż umów na inne kwoty).
The mode of wages and salaries is an important indicator describing their distribution; however, due to the strong asymmetry of the distribution of this feature in Poland, mode estimation is not a standard procedure in the analysis of the structure of wages and salaries. The aim of the article is to discuss selected methods of estimating the mode and to compare the mode estimation results obtained by means of various methods. The research is based on data on individual gross wages and salaries registered in October 2018 in Poland. The data came from a survey of the structure of wages and salaries conducted by Statistics Poland. In the case of the standard method based on the interpolation formula and histogram, the mode estimate is sensitive to the assumed span of intervals in the frequency table and the beginning of the first interval. Reducing the span of the intervals causes the mode to reach the value of the minimum wage. The application of advanced methods, including those using a kernel estimator, leads to significantly different estimates of the mode depending on the method used (the dispersion reaches the value of approximately PLN 800). Additionally, the analysis of the obtained results gives grounds to considering a thesis that wage and salary distribution is a mixture of the following distributions: discrete (for the minimum wage) and continuous (for wages and salaries above the minimum wage), and is characterised by cyclicality (in Poland, more contracts offer remunerations which are a multiple of PLN 50 or PLN 100 than remunerations for other amounts).
Źródło:
Wiadomości Statystyczne. The Polish Statistician; 2022, 67, 12; 62-79
0043-518X
Pojawia się w:
Wiadomości Statystyczne. The Polish Statistician
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetostatic analysis of a pinch mode magnetorheological valve
Autorzy:
Gołdasz, J.
Sapiński, B.
Powiązania:
https://bibliotekanauki.pl/articles/386794.pdf
Data publikacji:
2017
Wydawca:
Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej
Tematy:
MR fluid
pinch mode
valve
magnetostatic model
Opis:
The study deals with the pinch mode of magnetorheological (MR) fluids’ operation and its application in MR valves. By applying the principle in MR valves a highly non-uniform magnetic field can be generated in flow channels in such a way to solidify the portion of the material that is the nearest to the flow channel’s walls. This is in contrary to well-known MR flow mode valves. The authors investigate a basic pinch mode valve in several fundamental configurations, and then examine their magnetic circuits through magnetostatic finiteelement (FE) analysis. Flux density contour maps are revealed and basic performance figures calculated and analysed. The FE analysis results yield confidence in that the performance of MR pinch mode devices can be effectively controlled through electromagnetic means.
Źródło:
Acta Mechanica et Automatica; 2017, 11, 3; 229-232
1898-4088
2300-5319
Pojawia się w:
Acta Mechanica et Automatica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Quasi-Sliding Mode Control of Discrete-Time Systems
Autorzy:
Bartoszewicz, A.
Powiązania:
https://bibliotekanauki.pl/articles/908266.pdf
Data publikacji:
1999
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
sterowanie
system dyskretny
sliding-mode control
discrete-time systems
Opis:
A reaching law approach to the design of discrete-time quasi-sliding mode control systems is considered. First the required position of the system representative point with reference to the sliding plane is specified, and then novel control strategies, which drive the system in such a way that the position actually changes according to the specification, are proposed. The strategies are linear and consequently the undesirable chattering and high-frequency switching between different values of the control signal are avoided. Furthermore, the state of the controlled system is driven to the narrowest possible band around the sliding plane. The strategies, when compared with previously published results, are simpler and they guarantee favourable performance of the controlled systems while using essentially reduced control effort.
Źródło:
International Journal of Applied Mathematics and Computer Science; 1999, 9, 4; 801-810
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Averaged model of a buck DC–DC converter for single-loop description of current-mode control
Autorzy:
Janke, Włodzimierz
Bączek, Maciej
Kraśniewski, Jarosław
Powiązania:
https://bibliotekanauki.pl/articles/141131.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
averaged model
buck converter
continuous conduction mode
peak current
mode control
Opis:
: Averaged models: an AC large signal, DC and AC small signals of a currentcontrolled buck converter are described. Only peak current mode control of a converter working in the continuous conduction mode (CCM) is considered. The model derivation differs from the typical approaches presented in the literature and doesn’t refer to the multiloop concept of a current controlled converter. The separation of the variables method is used in the model derivation. The resulting models are presented in the form of an equation set and equivalent circuits. The calculations based on the presented models are verified by measurements and full-wave PSpice simulations.
Źródło:
Archives of Electrical Engineering; 2019, 68, 4; 891-905
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Simulation of a single mode wave generation in cylindrical systems applying numerical methods
Autorzy:
Gorazd, Łukasz
Snakowska, Anna
Powiązania:
https://bibliotekanauki.pl/articles/127909.pdf
Data publikacji:
2019
Wydawca:
Politechnika Poznańska. Instytut Mechaniki Stosowanej
Tematy:
cylindrical duct
multi-mode wave propagation
single mode generation
kanał cylindryczny
wielomodowa propagacja fali
generacja pojedynczego modu
Opis:
The paper presents simulations of a selected single mode generation in systems containing duct-like elements applying the finite element method (FEM). Simulations were carried out for values of the Helmholtz number exceeding the plane-wave propagation, i.e. for a multimode wave. The presented results constitute the first step to analyse propagation of the multimode wave through more complicated systems such as mufflers, even in a form of a cascade. Propagation of the incident wave in the form of a single mode greatly simplifies solutions of many problems, to mention only derivation of the transmission or the scattering matrices. The results obtained can be applied to analyse the effectiveness of attenuation of acoustic silencers or elements of heating, ventilation and air conditioning systems (HVAC) at the design stage. Results of simulations are compared with already published experimental data obtained in a measurement set-up containing the self-designed single mode synthesizer.
Źródło:
Vibrations in Physical Systems; 2019, 30, 1; 1-6
0860-6897
Pojawia się w:
Vibrations in Physical Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Resonance tests - vibration mode shapes from the wing torsion group
Autorzy:
Wiśniewski, W.
Powiązania:
https://bibliotekanauki.pl/articles/245897.pdf
Data publikacji:
2009
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
transport
aircraft
resonance tests
vibration mode
torsion wing
Opis:
Resonances of the „ wings torsion " mode shapes to a large extent depend on the structural parameters of the wing, and more specifically to the existence or not of fuel tanks at the wings ends, munitions hard points or engines mounted on the wings. In the paper the group of resonances is presented with mode shapes in which the one, two or three node aircraft wing torsion is present. It is shown in the paper, that these vibration mode shapes consist both of fuselage bending or torsion. Resonance frequencies with mode shapes in which one, two or three node wing torsion occurs depend fundamentally on existence of wing hardpoints. If hardpoints are occupied by fuel tanks, these frequencies are varying continuously in wide range. The various interesting from cognitive point of view combinations have place then, including variable frequencies and variable mode shapes as a function of fuel consumption. The aim for the analysis of 3 cases of resonance a wing torsion mode shapes of airplanes and gliders was to investigate the relationships and mechanisms that are taking place and operate between the torsioningl vibration of the wings and bending or torsion vibrations of the fuselage. Recognition of these phenomena should facilitate the researcher to understand and search effectively and explore the resonances of„ wing torsion " mode shapes.
Źródło:
Journal of KONES; 2009, 16, 4; 557-561
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Problems of propulsion arrangement choice of multi-mode ship
Autorzy:
Herdzik, J.
Powiązania:
https://bibliotekanauki.pl/articles/246914.pdf
Data publikacji:
2010
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
ships propulsion
propulsion arrangement
multi-mode ships
propulsion choice
Opis:
The propulsion system of multi-mode ships cause many problems of proper the choise of propulsion system elements and theirs arrangement in the design process. This system has to fulfil at least two inverse demands. It ought to make possible efficient ship shift (transit mode) from the port to the off shore work place and return to base, to ensure a ship survive at sea in the worst sea condition possible on that sea area and to fulfil conditions of dynamic positioning accuracy (stationkeeping mode) at specified bad state of the sea - not to stop the ship work for long time. The dynamic positioning systems require multi-element ship propulsion application. The fulfilment, all required possibilities and accuracy of ship positioning by chosen propulsion system specified in the project data, is the most important project problem to obtain the minimum investment costs. The redimensioning of propulsion system, increasing the number of thrusters and theirs possibilities gives the benefits in dynamic positioning accuracy, but increases the investment costs. An expensive project may not be realized because of price. The aim of designer is the choice optimum solution of propulsion system, which is fulfils all expectations of ship owner and crew, and performs all project assumptions.
Źródło:
Journal of KONES; 2010, 17, 2; 129-135
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Localized plasma polarimetry based on the phenomenon of normal mode conversion
Autorzy:
Kravtsov, , Y. A.
Bieg, B.
Powiązania:
https://bibliotekanauki.pl/articles/146670.pdf
Data publikacji:
2011
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
plasma
polarimetry
mode conversion
Opis:
A new geometry of microwave polarimetric measurements is presented, which realizes a localized plasma polarimetry based on the phenomenon of electromagnetic mode conversion. Such a conversion takes place in the tokamak plasma, in the vicinity of the point where the microwave beam is orthogonal to one of the helical magnetic lines. In distinction to the traditional plasma polarimetry, which deals with the line averaged plasma parameters, the new methodology allows for a measurement of the local values of plasma parameters near the point of orthogonality. This methodology was shown to be very efficient in studies of the solar radio emission and polarization properties of radio waves passing through the Earth ionosphere. In the following the theory of electromagnetic mode conversion is described and conditions of its applicability are analyzed. It is shown that localized polarimetric measurements of plasma parameters in the geometry of the international thermonuclear experimental reactor (ITER) device would require very high electron densities Ne, exceeding 1017 cm–3, i.e. thousand times higher than those envisaged in the ITER project.
Źródło:
Nukleonika; 2011, 56, 2; 171-174
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Energy of intrinsic mode function for gas-liquid flow pattern identification
Autorzy:
Sun, Z.
Gong, H.
Powiązania:
https://bibliotekanauki.pl/articles/221137.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
gas-liquid flow pattern
flow-pattern map
pressure fluctuation
bluff body
signal energy
intrinsic mode function
empirical mode decomposition
Opis:
Gas-liquid flows abound in a great variety of industrial processes. Correct recognition of the regimes of a gas-liquid flow is one of the most formidable challenges in multiphase flow measurement. Here we put forward a novel approach to the classification of gas-liquid flow patterns. In this method a flow-pattern map is constructed based on the average energy of intrinsic mode function and the volumetric void fraction of gas-liquid mixture. The intrinsic mode function is extracted from the pressure fluctuation across a bluff body using the empirical mode decomposition technique. Experiments adopting air and water as the working fluids are conducted in the bubble, plug, slug, and annular flow patterns at ambient temperature and atmospheric pressure. Verification tests indicate that the identification rate of the flow-pattern map developed exceeds 90%. This approach is appropriate for the gas-liquid flow pattern identification in practical applications.
Źródło:
Metrology and Measurement Systems; 2012, 19, 4; 759-766
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Temperature dependence of polarization mode dispersion in tight-buffered optical fibers
Autorzy:
Borzycki, K.
Powiązania:
https://bibliotekanauki.pl/articles/308525.pdf
Data publikacji:
2008
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
single mode optical fiber
polarization mode dispersion
birefringence
environmental testing
tight buffered fiber
optical fiber cable
optical ground wire
temperature cycling
polymer
Opis:
Experiments and theoretical analysis of influence of temperature on polarization mode dispersion (PMD) in single mode optical fibers and cables are presented. Forces generated by contracting buffer create optical birefringence and increase fiber PMD at low temperatures. Single mode fiber (SMF) in 0.9 mm polymeric tight-buffer can exhibit an extra component of PMD exceeding 0.3 ps/?km in such conditions. On the other hand, tight-buffered spun nonzero dispersion-shifted fibers (NZDSF) and optical units with stranded single mode fibers have showed good stability of PMD over wide range of temperatures. This is due to presence of circular strain in the core, blocking accumulation of mechanically induced birefringence.
Źródło:
Journal of Telecommunications and Information Technology; 2008, 1; 56-66
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Progress in theoretical models of the ICRF mode conversion
Autorzy:
Kazakov, Y. O.
Powiązania:
https://bibliotekanauki.pl/articles/147690.pdf
Data publikacji:
2012
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
ICRF heating
ion-ion hybrid resonance
mode conversion
tokamak
Opis:
The technique of heating the plasma with the electromagnetic waves in the ion cyclotron range of frequencies (ICRF) has many important applications that may lead to improved performance of tokamaks. Recently the heating efficiency of the ICRF mode conversion scenarios characterized by a narrow power deposition profiles received much attention. This paper highlights progress in the theoretical models of the ICRF mode conversion that allowed to achieve a successful experimental realisation of these scenarios in present-day tokamaks.
Źródło:
Nukleonika; 2012, 57, 1; 31-35
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application possibilities of electric driven propulsion of multi-mode ships
Autorzy:
Herdzik, J.
Powiązania:
https://bibliotekanauki.pl/articles/246217.pdf
Data publikacji:
2010
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
ships propulsion
electric propulsion
multi-mode ships
propulsion systems
Opis:
The ship propulsion solution based on unconventional thrusters driven by electric motors is most often applied for the multi-mode ships. These ships ought to have dynamic positioning system. It forces an application of a few thrusters (most often four, seldom more up to eight). Records from a number of multi-mode ships show amean load of less than 40% of maximum load on the propulsion system. In other side the demand for electric energy of ship industrial part is large, more often than for the propulsion part. In that case the diesel-electric propulsion system application may be economical, because the electric energy generation for all ship's purposes makes possible the main engines work on the optimum loads on lowest specific fuel consumption and allows them a long-term work on heavy fuels. For multi-mode ships like cable ships, suppliers, drilling vessels are convenient an application of unconventional thrusters with direct electric propulsion as well, especially for dynamic positioning systems. The efficiency of the thrusters is a predominant factor for the successful and economical operation. Forecasted development and rise of quantity of diesel-electric propulsion (it means with electrical transmission) would cause increased interest of unconventional thrusters. Ultimately they may revolutionize ship propulsion systems.
Źródło:
Journal of KONES; 2010, 17, 1; 163-168
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application possibilities of electric driven propulsion of multi-mode ships
Autorzy:
Herdzik, J.
Powiązania:
https://bibliotekanauki.pl/articles/247580.pdf
Data publikacji:
2010
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
ships propulsion
electric propulsion
multi-mode ships
propulsion systems
Opis:
The ship propulsion solution based on unconventional thrusters driven by electric motor s is most often applied for the multi-mode ships. These ships ought to have dynamic positioning system. It forces an application of a few thrusters (most often four, seldom more up to eight). Records from a number of multi-mode ships show a mean load of less than 40% of maximum load on the propulsion system. In other side the demand for electric energy of ship industrial part is large, more often than for the propulsion part. In that case the diesel-electric propulsion system application may be economical, because the electric energy generation for all ship 's purposes makes possible the main engines work on the optimum loads on lowest specific fuel consumption and allows them a long-term work on heavy fuels. For multi-mode ships like cable ships, suppliers, drilling vessels are convenient an application of unconventional thrusters with direct electric propulsion as well, especially for dynamic positioning systems. The efficiency of the thrusters is a predominant factor for the successful and economical operation. Forecasted development and rise of quantity of diesel-electric propulsion (it means with electrical transmission) would cause increased interest of unconventional thrusters. Ultimately they may revolutionize ship propulsion systems.
Źródło:
Journal of KONES; 2010, 17, 4; 177-183
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Perturbation Element Effect on Frequency Stability in Dual Mode Reconfigurable Filters Based on Circular Microstrip Ring Resonators
Autorzy:
Albahnassi, Muhammad Haitham
Malki, Adnan
Almekdad, Shokri
Powiązania:
https://bibliotekanauki.pl/articles/227210.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
dual mode ring resonators
dual-mode filters
perturbation element arrangement
BW reconfigurability
Opis:
A detailed study about the suitable perturbation element shape and location for tunable BW dual mode microstrip filter which has circular ring resonator is presented. BW tuning is achieved by resonator geometry modification. The study explains the effect of a perturbation element on the stability of the center frequency during BW tuning. Different cases have been studied for two shapes of perturbation element; which one is a rectangular and the other is a radial. The treated cases discuss whether the perturbation element is located in the inner or in the outer circumference of the ring, and whether it is a patch or a notch. BW tuning simulation treated the case of FBW3dB increase for two and three times. The best case of perturbation element which has the best center frequency stability has been modeled, simulated, and fabricated at 2.4 GHz. Geometry modification of the filter took into account the RF MEMS modeling. The filter has an elliptic frequency response, and its FBW has been increased in five steps from 1.7% to 5%. The designed filters were evaluated experimentally and by simulation with very good agreement.
Źródło:
International Journal of Electronics and Telecommunications; 2019, 65, 4; 731-737
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Stability analysis of sliding-mode feedback control
Autorzy:
Clarke, F. H.
Vinter, R. B.
Powiązania:
https://bibliotekanauki.pl/articles/970887.pdf
Data publikacji:
2009
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
sliding-mode control
discontinuous control
Lyapunov functions
stabilization
robustness
Opis:
This paper provides new analytic tools leading to the first rigorous stability and robustness analysis of sliding-mode feedback controllers. Unrestrictive conditions are given, under which these controllers are stabilizing in the presence of large disturbances, conditions invoke the existence of two Lyapunov-type functions, the first associated with passage to the sliding set in finite time, and the second with convergence to the desired state. In this approach, account is taken, from the outset, of implementational constraints. We provide a framework for establishing stability and robustness of the closed-loop system, for a variety of implementation schemes. We illustrate our results by means of two examples of the type frequently encountered in the sliding-mode literature.
Źródło:
Control and Cybernetics; 2009, 38, 4A; 1169-1192
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Survey Addressing on High Performance On-Chip VLSI Interconnect
Autorzy:
Mohamed Yousuff, C.
Mohamed Yousuf Hasan, V.
Khan Galib, M. R.
Powiązania:
https://bibliotekanauki.pl/articles/226784.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
current-mode signaling
hybrid current/voltage mode circuits
on-chip interconnects delay and power
voltage mode signaling
Opis:
With the rapid increase in transmission speeds of communication systems, the demand for very high-speed lowpower VLSI circuits is on the rise. Although the performance of CMOS technologies improves notably with scaling, conventional CMOS circuits cannot simultaneously satisfy the speed and power requirements of these applications. In this paper we survey the state of the art of on-chip interconnect techniques for improving performance, power and delay optimization and also comparative analysis of various techniques for high speed design have been discussed.
Źródło:
International Journal of Electronics and Telecommunications; 2013, 59, 3; 307-312
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Static and dynamic interactive buckling regarding axial extension mode of thin-walled channel
Autorzy:
Kołakowski, Z.
Powiązania:
https://bibliotekanauki.pl/articles/279999.pdf
Data publikacji:
2010
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
thin-walled structures
dynamic interactive buckling
axial mode
Opis:
The present paper deals with an influence of the axial extension mode on static and dynamic interactive buckling of a thin-walled channel with imperfections subjected to uniform compression when the shear lag phenomenon and distortional deformations are taken into account. A plate model is adopted for the channel. The structure is assumed to be simply supported at the ends. Equations of motion of component plates were obtained from Hamilton's principle taking into account all components of inertia forces. In the frame of first order nonlinear approximation, the dynamic problem of modal interactive buckling is solved by the transition matrix using the perturbation method and Godunov's orthogonalization.
W prezentowanej pracy omówiono wpływ osiowej wzdłużnej postaci na statyczne i dynamiczne interakcyjne wyboczenie cienkościennego ceownika z niedokładnościami poddanego równomiernemu ściskaniu przy uwzględnieniu zjawiska shear-lag oraz dystorsyjnej deformacji. Przyjęto płytowy model ceownika. Konstrukcja jest przegubowo podparta na obu końcach. Równania ruchu płyt składowych otrzymano z zasady Hamiltona, biorąc pod uwagę wszystkie składowe sił bezwładności. Dynamiczne zagadnienie modalnego interakcyjnego wyboczenia w ramach pierwszego rzędu nieliniowej aproksymacji rozwiązano metodą macierzy przeniesienia i metodą ortogonalizacji Godunova.
Źródło:
Journal of Theoretical and Applied Mechanics; 2010, 48, 3; 703-714
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Continuous and discrete sliding mode control of an active car suspension system
Autorzy:
Łuczko, J.
Ferdek, U.
Powiązania:
https://bibliotekanauki.pl/articles/280694.pdf
Data publikacji:
2016
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
sliding mode control
active damping
car suspension
Opis:
In this paper, sliding mode control (SMC) algorithms are tested for their use in an active car suspension system. Using the quarter model of the car as an example, the comparison of the efficiency of the algorithms is made. A continuous and two discrete versions of the sliding mode control are taken into consideration. The study is limited to finding the relation between the control parameters and the comfort factor. This is done by analyzing the response of the model to the harmonic and impulse excitation.
Źródło:
Journal of Theoretical and Applied Mechanics; 2016, 54, 1; 3-11
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Adaptive sliding mode control for ship autopilot with speed keeping
Autorzy:
Liu, Z.
Powiązania:
https://bibliotekanauki.pl/articles/259349.pdf
Data publikacji:
2018
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
surface vessel
speed loss
adaptive control
course keeping
sliding mode control
Opis:
The paper addresses an important issue in surface vessel motion control practice that the ship dynamics and sailing performance can be affected by speed loss. The vessel speed is significantly decreased by the added resistance generated by waves. An adaptive sliding mode course keeping control design is proposed which takes into account uncertain ship dynamics caused by forward speed variations, while avoiding performance compromises under changing operating and environmental conditions. The sliding mode control provides robust performance for time-varying wave disturbances and time-varying changes in ship parameters and actuator dynamics. After combining the unknown but bounded system uncertainties, the design of the adaptation law is obtained which is based on the Lyapunov’s direct method. Simulations on a ship with two rudders illustrate the effectiveness of the proposed solution.
Źródło:
Polish Maritime Research; 2018, 4; 21-29
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
CMOS ECCCII with Linear Tune of Rx and Its Application to Current-Mode Multiplier
Autorzy:
Sakul, C.
Powiązania:
https://bibliotekanauki.pl/articles/226547.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
electronically tunable
CCCII
current mode
CMOS
linear
Opis:
In this paper, the second-generation CMOS currentcontrolled-current-conveyor based on differential pair of operational transconductance amplifier has been researched and presented. Since the major improvement of its parasitic resistance at x-port can be linearly controlled by an input bias current, the proposed building block is then called “The Second-Generation Electronically-tunable Current-controlled Current Conveyor” (ECCCI). The applications are demonstrated in form of both 2 quadrant and 4 quadrant current-mode signal multiplier circuits. Characteristics of the proposed ECCCII and its application are simulated by the PSPICE program from which the results are proved to be in agreement with the theory.
Źródło:
International Journal of Electronics and Telecommunications; 2018, 64, 3; 385-390
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
COMPUTER-BASED (CBT) VS. PAPER-BASED (PBT) TESTING: MODE EFFECT, RELATIONSHIP BETWEEN COMPUTER FAMILIARITY, ATTITUDES, AVERSION AND MODE PREFERENCE WITH CBT TEST SCORES IN AN ASIAN PRIVATE EFL CONTEXT
Autorzy:
Khoshsima, Hooshang
Toroujeni, Seyyed Morteza Hashemi
Thompson, Nathan
Ebrahimi, Mohammad Reza
Powiązania:
https://bibliotekanauki.pl/articles/955443.pdf
Data publikacji:
2019
Wydawca:
Uniwersytet Marii Curie-Skłodowskiej w Lublinie. IATEFL Poland Computer Special Interest Group
Tematy:
Computer-Based Testing
testing administration mode
computer familiarity
attitudes and aversion
testing administration mode preference
Opis:
The current study was conducted to investigate whether test scores of Iranian English as Foreign Language (EFL) learners were equivalent across CBT and PBT modes, with 58 intermediate learners studying at a private language academy located in Behshahr city in northern Iran. Moreover, test takers’ computer familiarity, attitudes, aversion, and testing mode preference were regarded as the potential issues to influence CBT test scores. Data were collected using CBT and PBT versions of Nelson Proficiency Multiple-Choice Tests and Computer Aversion, Attitudes, and Familiarity Index (CAAFI) questionnaire as well as a simple testing administration mode preference question. The participants produced similar scores across modes, although they insignificantly outperformed on the CBT version. Additionally, analysis of the overall scores on the CAAFI and mode preference question obtained from CBT testing session indicated no statistically significant correlation between computer familiarity, attitude, aversion, and mode preference variables and test takers’ CBT scores. The qualitative findings of this study obtained by semi-structured interview revealed that most of the participants showed high preference and more advantages for CBT over PBT to rationalize why they preferred this mode of testing.
Źródło:
Teaching English with Technology; 2019, 19, 1; 86-101
1642-1027
Pojawia się w:
Teaching English with Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Narrow transmission mode in one-dimensional symmetric defective photonic crystal containing metamaterial and high Tc superconductor
Autorzy:
Srivastava, Sanjeev K.
Aghajamali, Alireza
Powiązania:
https://bibliotekanauki.pl/articles/173630.pdf
Data publikacji:
2019
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
photonic crystal
photonic band gap
transmission spectra
transmission mode
defect mode
metamaterial
negative index material
superconductor photonic crystal
Opis:
We theoretically investigate the properties of narrow transmission mode (defect mode) within the reflection band in one-dimensional symmetric defective photonic crystal containing double negative metamaterial and high temperature superconductors. The transmittance spectrum of the proposed structure is obtained by using the characteristic or transfer matrix method. The results show that by increasing the thickness of air defect, transmission mode shifts towards the lower frequency side. But when the thickness of a superconductor layer is increased, transmission mode shifts towards the high frequency side. Further, the effect of temperature variation of superconducting defect on the defect mode has been investigated and found that when the temperature of superconducting layer increases the frequency of defect mode is red shifted. The shift in frequency has smaller value in the lower temperature region than in the higher temperature region, even if the change in temperature is same. Finally we have discussed the effect of variation of thickness on the defect mode by using the double negative metamaterial as defect layer in place of superconductor layer. The result shows that we get two modes for smaller thickness of double negative layer but only a single mode for larger thickness.
Źródło:
Optica Applicata; 2019, 49, 1; 37-50
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mode of life of graptolites
Autorzy:
Hartshorne Kirk, N.
Powiązania:
https://bibliotekanauki.pl/articles/22778.pdf
Data publikacji:
1978
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Źródło:
Acta Palaeontologica Polonica; 1978, 23, 4
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Topic- and Mode-Sensitive Interaction Strategies: Functions of Ellipsis in Oral Communication
Autorzy:
White, Jonathan
Powiązania:
https://bibliotekanauki.pl/articles/620837.pdf
Data publikacji:
2015-09-01
Wydawca:
Uniwersytet Łódzki. Wydawnictwo Uniwersytetu Łódzkiego
Tematy:
ellipsis
interaction
oral discourse
textchat
discourse topic
mode of communication
Opis:
In this article, we discuss ellipsis as an interactive strategy by analysing the author’s textchat corpus and the VOICE corpus of English as a Lingua Franca. It is found that there were fewer repetitions in the textchat data, and this is explained as a consequence of the textchat mode. Textchat contributions are preserved as long as the chat is active or has been saved, and therefore users can scroll through and review the discussion, compared to the more fleeting nature of oral conversation. As a result, repetition is less necessary. The frequency of other functions identified could be attributed to the topic of discourse. Discussions involve much ellipsis used to develop discourse, although some were self-presentations with repetition used to confirm details. Back-channel support and comments were often low because speakers instead used forms like yeah as supportive utterances.
Źródło:
Research in Language; 2015, 13, 3; 334-350
1731-7533
Pojawia się w:
Research in Language
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Continual mode transformation in a unidirectional compound waveguide
Autorzy:
Kong, W.
Cai, Q.
Lin, Z.-L.
Fang, Y.-T.
Powiązania:
https://bibliotekanauki.pl/articles/173535.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
mode transformation
unidirectional waveguide
metal slabs
Opis:
We propose a new mechanism to achieve mode transformation. In a unidirectional air waveguide we place some metal slabs to form the unidirectional edge loop. Based on the effect of mode interference, the even mode or the odd mode can be completely canceled from their degenerated state through a precise adjustment of slab position, which leads to another mode to be released. By this mechanism, we have achieved continual transformations between even mode and odd mode.
Źródło:
Optica Applicata; 2018, 48, 1; 87-94
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Chattering attenuation in sliding mode control systems
Autorzy:
Bartoszewicz, A.
Powiązania:
https://bibliotekanauki.pl/articles/206731.pdf
Data publikacji:
2000
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
nieliniowy system sterowania
nonlinear control system
compensation
control nonlinearities
sliding mode control
variable structure systems
Opis:
In this paper sliding mode control systems are considered and a new technique to attenuate chattering is proposed. The technique employs simple, first-order dynamical devices, i.e. an integrator or a low-pass filter, to compensate in part for unknown and changing disturbance. As a result of this compensation, the magnitude of the discontinuous control term is essentially reduced. The term does not depend on the admissible disturbance or its change rate, but only on the uncertainty of the disturbance at the initial time t = t[sub o]. The technique proposed in this paper attenuates the undesirable chattering without any deterioration of the system performance.
Źródło:
Control and Cybernetics; 2000, 29, 2; 585-584
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Control of an Induction Motor Using Sliding Mode Linearization
Autorzy:
Etien, E.
Cauet, E.
Rambault, L.
Champenois, G.
Powiązania:
https://bibliotekanauki.pl/articles/908504.pdf
Data publikacji:
2002
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
automatyka
induction motor
sliding mode control
linearization
Opis:
Nonlinear control of the squirrel induction motor is designed using sliding mode theory. The developed approach leads to the design of a sliding mode controller in order to linearize the behaviour of an induction motor. The second problem described in the paper is decoupling between two physical outputs: the rotor speed and the rotor flux modulus. The sliding mode tools allow us to separate the control from these two outputs. To take account of parametric variations, a model-based approach is used to improve the robustness of the control law despite these perturbations. Experimental results obtained with a laboratory setup illustrate the good performance of this technique.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2002, 12, 4; 523-531
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of temperature and aging on polarization mode dispersion of tight-buffered optical fibers and cables
Autorzy:
Borzycki, K.
Powiązania:
https://bibliotekanauki.pl/articles/309050.pdf
Data publikacji:
2005
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
single mode optical fiber
polarization mode dispersion
environmental testing
tight buffered fiber
optical fiber cable
optical ground wire
thermal cycling
accelerated life test
Opis:
This paper presents results of laboratory tests investigating influence of temperature on polarization mode dispersion (PMD) in variety of single mode optical fibers and cables. Research was focused primarily on tight-buffered fibers, where most pronounced effects resulting from buffer shrinkage or expansion were expected. The goal was to verify performance of optical fiber cable exposed to extreme temperatures and to compare behavior of different cables. Very strong temperature dependence of PMD was detected in standard single mode fibers with 0.9 mm tight buffer, commonly used in indoor cables, and in complete cable with such fiber. However, both nonzero dispersion-shifted fibers, spun during drawing and optical unit used in optical ground wire (OPGW), where 12 fibers are stranded showed good stability of PMD during thermal cycling. The same optical unit extracted from OPGW exhibited excellent PMD stability also during accelerated life test.
Źródło:
Journal of Telecommunications and Information Technology; 2005, 3; 96-104
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fall-Back Mode Operation on Remotely Controlled Railway Lines
Autorzy:
Cseh, Attila
Sághi, Balázs
Tarnai, Géza
Powiązania:
https://bibliotekanauki.pl/articles/504196.pdf
Data publikacji:
2015
Wydawca:
Międzynarodowa Wyższa Szkoła Logistyki i Transportu
Tematy:
railway
CTC
remote control
operational control centre
fall-back mode
Opis:
This paper deals with handling abnormal situations raised on remotely controlled railway lines, in particular how to maintain an automatic operation that is a core function of such systems. Unlike conventional traffic control, in case of remotely controlled stations the operational personnel is not located on the stations, thus nobody can intervene in the railway traffic locally, if necessary. In addition, replacing staff with technical devices and automatism makes the number of potential failure modes even higher. The most critical event happens when the data connection between the control centre and the station is lost, so that the human supervision of the traffic terminates. This paper presents the human, technological and technical aspects of treating such failures and offers some potential solutions in order to maintain railway traffic and minimize disturbances.
Źródło:
Logistics and Transport; 2015, 26, 2; 49-56
1734-2015
Pojawia się w:
Logistics and Transport
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Theoretical analysis of magnetorheological damper characteristics in squeeze mode
Autorzy:
Sapiński, B.
Powiązania:
https://bibliotekanauki.pl/articles/386653.pdf
Data publikacji:
2015
Wydawca:
Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej
Tematy:
MR Damper
squeeze mode
gap
force
characteristic
silnik samochodowy
ciecz magnetoreologiczna
tłumik magnetoreologiczny
MR
Opis:
The paper summarises the theoretical study of a magnetorheological (MR) damper operated in squeeze mode, intended to be used as an actuator in a semi-active mount system in a car motor. The structural design and operating principle of the damper are described and a simplified model of the MR fluid flow in the gap is presented. The plots of the damper force generated by the MR damper are obtained for monoharmonic piston motion with respect to the centre point of the gap height and in the conditions of the control coil being supplied with direct current.
Źródło:
Acta Mechanica et Automatica; 2015, 9, 2; 89-92
1898-4088
2300-5319
Pojawia się w:
Acta Mechanica et Automatica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A mode-III crack with variable surface effects
Autorzy:
Wang, X.
Schiavone, P.
Powiązania:
https://bibliotekanauki.pl/articles/282009.pdf
Data publikacji:
2016
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
surface elasticity
variable surface moduli
mode-III crack
Cauchy singular integro-differential equation
Opis:
We study the contribution of variable surface effects to the antiplane deformation of a linearly elastic material with a mode-III crack. The surface elasticity is incorporated using a modified version of the continuum based surface/interface model of Gurtin and Murdoch. In our discussion, the surface moduli are not constant but vary along the crack surfaces. Using Green’s function method, the problem is reduced to a single first-order Cauchy singular integro-differential equation, which is solved numerically using Chebyshev polynomials and a collocation method. Our results indicate that the gradient of the surface shear modulus exerts a significant influence on the crack opening displacement and on the singular stress field at the crack tips.
Źródło:
Journal of Theoretical and Applied Mechanics; 2016, 54, 4; 1319-1327
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Observations of MR fluid clumping behaviour in a squeeze-mode damper
Autorzy:
Sapiński, B.
Powiązania:
https://bibliotekanauki.pl/articles/386939.pdf
Data publikacji:
2016
Wydawca:
Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej
Tematy:
MR fluid
squeeze mode
damper
clumping behaviour
tłumik drgań
płyny
mechanika płynów
Opis:
The study summarises the results of quasi-static experimental tests of an MR squeeze-mode damper prototype (MRSQD) performed at the MTS testing machine. Of particular interests was the influence of MR fluid clumping behaviour in the MRSQD working gap on the force output of the device. The MRSQD tests were assessed by measuring the damping force output at prescribed sinusoidal displacement inputs and at various (fixed) voltage levels resulting in the respective average current levels in the control coil. The influence of piston position offset on the damping force was also investigated. The collected data were shown in the form of damping force time histories and damping force-piston displacements loops and discussed with respect to MR fluid clumping behaviour.
Źródło:
Acta Mechanica et Automatica; 2016, 10, 3; 239-245
1898-4088
2300-5319
Pojawia się w:
Acta Mechanica et Automatica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Propulsion characteristics of multi-mode ships in aspect of ships dynamic positioning application
Autorzy:
Herdzik, J.
Powiązania:
https://bibliotekanauki.pl/articles/243980.pdf
Data publikacji:
2010
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
ships propulsion
propulsion characteristics
multi-mode ships
dynamic positioning systems
Opis:
The dynamic positioning systems require multi-element ship propulsion application. The chosen solutions have decisive effect on propulsion system possibilities, in ship dynamic positioning accuracy also. The automation system has an essential influence on it, because it is an integral part with propulsion system mponsible for this process. The most often ship propulsion solution based on unconventional thrusters driven by electric motor s also. A few independent propulsion systems is essential but it complicates this system, it is limited the number (most often to 4, seldom more up to eight). There are no solutions with traditional rudder and steering gear. These functions take over azimuthing thrusters because they can generale directional thrust force. It must be settle the question of the number of thruster choose and the span angle of azimuthing (most often by thruster turning). In that case it gets the possibilities of ship positioning, they may display as propulsion system characteristics, giving a view on ąuality of positioning process. The last veriflcation is made in real sea conditions when it may test if chosen solution of ship propulsion system fulfils the requirements of positioning accuracy. It was presented the examples of multi-mode ship propulsions and parameters of theirs propulsion plants.
Źródło:
Journal of KONES; 2010, 17, 3; 127-134
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
L'objet iconique dans La vie mode d'emploi de Georges Perec
Przedmiot ikoniczny w La vie mode d'emploi Georges'a Pereca
Autorzy:
Sobczyński, Krzysztof
Powiązania:
https://bibliotekanauki.pl/articles/2121396.pdf
Data publikacji:
1999
Wydawca:
Katolicki Uniwersytet Lubelski Jana Pawła II. Towarzystwo Naukowe KUL
Opis:
Opublikowana w roku 1976 powieść Pereca La vie mode d'emploi zdaje się w jego twórczości zajmować miejsce szczególne, miejsce opus magnum, w którym autor zawarł sumę swoich przemyśleń o literaturze i w którym spotykają się wszystkie tendencje obecne w jego różnorodnym dziele. Najpełniej realizuje ona postulat „czterech horyzontów”, o których wspominał Perec w wielu wywiadach i autokomentarzach. Powieść ta jest także znakomitą okazją do prześledzenia, jaką rolę odgrywa w tym pisarstwie przedmiot ikoniczny. Termin ten określa wszelkiego rodzaju przedmioty przedstawiające, od obrazu znanego malarza po kartkę pocztową i fotografię. Przedmiot ikoniczny stanowi w pisarstwie Pereca punkt wyjścia do „produkowania” tekstu (poprzez bardzo skomplikowany system contraintes), ale jest też bezpośrednio obecny w tekście, zastępując niejako klasyczny opis. Można go również traktować jako jeden z zasadniczych topoi Pereca, poprzez które pisarz wypowiada się najpełniej i najbardziej bezpośrednio. W niniejszym artykule (będącym jednym z rozdziałów rozprawy doktorskiej zatytułowanej L'objet iconique dans l'œuvre de Georges Perec) starałem się ukazać tę właśnie złożoną funkcję przedmiotu ikonicznego.
Źródło:
Roczniki Humanistyczne; 1999, 46-47, 5; 5-50
0035-7707
Pojawia się w:
Roczniki Humanistyczne
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Availability of maritime radio beacon signals for R-Mode in the Southern Baltic Sea
Autorzy:
Gewies, S.
Grundhöfer, L.
Hehenkamp, N.
Powiązania:
https://bibliotekanauki.pl/articles/116740.pdf
Data publikacji:
2020
Wydawca:
Uniwersytet Morski w Gdyni. Wydział Nawigacyjny
Tematy:
radio navigation
radio beacon
R-Mode
Southern Baltic Sea
radio beacon Signals
maritime radio beacon
ranging mode
positioning
Navigation and Timing (PNT)
Opis:
This paper presents an overview of the development of a terrestrial positioning system called Ranging Mode (R-Mode) in the Southern Baltic Sea region which utilizes already existing maritime radio infrastructure. Here, an R-Mode testbed is planned to be set up until 2020 that meets maritime user needs for resilient PNT. First measurements of radio beacon signals on-board a vessel sailing in the Southern Baltic Sea show the good availability of beacon signals in this region. A comparison of received signals with a coverage prediction based on the nominal range of radio beacons shows the shortcoming of this approach and emphasizes the need for more elaborated coverage predictions which consider all effects of medium frequency wave propagation at day and night. In the measurements results the skywave has a major impact on the beacon signal stability in the night. The time stability of the signal amplitude seems to be a good indicator for disturbed reception conditions.
Źródło:
TransNav : International Journal on Marine Navigation and Safety of Sea Transportation; 2020, 14, 1; 170-163
2083-6473
2083-6481
Pojawia się w:
TransNav : International Journal on Marine Navigation and Safety of Sea Transportation
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ankieta internetowa jako element mixed-mode survey design: zastosowania, wyzwania perspektywy
Online questionnaire as part of mixed-mode survey design. Applications. Challenges. Perspectives
Autorzy:
Rybak, Adam
Powiązania:
https://bibliotekanauki.pl/articles/972962.pdf
Data publikacji:
2017
Wydawca:
Uniwersytet Opolski
Tematy:
ankieta internetowa
sondaż internetowy
kwestionariusz internetowy
mieszanie technik sondażu
web survey
online questionnaire
mixed-mode survey design
Opis:
Celem artykułu jest przedstawienie obecnego stanu wiedzy na temat możliwości i celowości wykorzystania techniki ankiety internetowej w przeprowadzaniu badań sondażowych w schemacie mixed-mode. Ze względu na rosnące trudności w realizacji sondaży w sposób tradycyjny konieczne jest poszukiwanie nowych rozwiązań. Artykuł przedstawia główne trudności związane z zastosowaniem techniki internetowej, oraz opisane w literaturze skuteczne sposoby ich minimalizacji w niektórych obszarach, przede wszystkim poprzez mieszanie technik na wszystkich etapach badania. Wskazuje także obszary, w których obecny stan wiedzy jest niewystarczający i konieczne jest przeprowadzenie dalszych badań eksperymentalnych.
The aim of the article is to present the current knowledge on the possibilities and the advisability of the use of online survey mode in conducting surveys in the mixed-mode design. Due to the increasing difficulty in the realization of survey research in the traditional way, it is necessary to search for new solutions. The article presents the main difficulties associated with the use of Web mode, and ways of minimizing them in some areas, mainly by mixing modes in all stages of research. The solutions are based on experiments results published in international methodological literature. Eventually it indicates areas where the current knowledge is inadequate and it is necessary to carry out further experimental research.
Źródło:
Studia Krytyczne/ Critical Studies; 2017, 4; 27-43
2450-9078
Pojawia się w:
Studia Krytyczne/ Critical Studies
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Distributive differential modals
Autorzy:
Ślusarska, Karolina
Powiązania:
https://bibliotekanauki.pl/articles/728834.pdf
Data publikacji:
2008
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
differential groupoid
mode
modal
Opis:
A differential modal is an algebra with two binary operations such that one of the reducts is a differential groupoid and the other is a semilattice, and with the groupoid operation distributing over the semilattice operation. The aim of this paper is to show that the varieties of entropic and distributive differential modals coincide, and to describe the lattice of varieties of entropic differential modals.
Źródło:
Discussiones Mathematicae - General Algebra and Applications; 2008, 28, 1; 29-47
1509-9415
Pojawia się w:
Discussiones Mathematicae - General Algebra and Applications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation of MR fluids in the oscillatory squeeze mode
Autorzy:
Sapiński, B.
Horak, W.
Szczęch, M.
Powiązania:
https://bibliotekanauki.pl/articles/386783.pdf
Data publikacji:
2013
Wydawca:
Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej
Tematy:
MR fluid
oscillatory squeeze mode
experiments
ciecz MR
doświadczenia
ciecz magnetoreologiczna
Opis:
The paper summarises the results of laboratory testing of three commercially available magnetorheological (MR) fluids operated in the oscillatory squeeze mode. Tested fluids include the Basonetic 204 and Basonetic 4035 (BASF) and MRF-122EG (Lord Corporation). The oscillatory squeeze mode produces large forces at small displacements. This feature may be well utilised in fabrication of new MR de-vices. The purpose of the experiments was to evaluate the suitability of MR fluids for applications in MR vibration dampers being devel-oped under the current research project. The results enable a comparative analysis of investigated fluids and verification of phenomena encountered in the oscillatory squeeze mode and reported in the literature.
Źródło:
Acta Mechanica et Automatica; 2013, 7, 2; 111-116
1898-4088
2300-5319
Pojawia się w:
Acta Mechanica et Automatica
Dostawca treści:
Biblioteka Nauki
Artykuł
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